A track guided vehicle system uses track guided vehicles to transport articles in a clean room, in a general factory, hospital, or library, or outdoors. Branching is required to provided a complicated layout of running tracks. The Unexamined Japanese Patent Application Publication (Tokkai) No. 2003-212112 discloses branching control of a track guided vehicle system. In the Unexamined Japanese Patent Application Publication (Tokkai) No. 2003-212112, a branching portion of the running track is provided with paired guide grooves for rectilinear progression and for branching. Further, a track guided vehicle is provided with paired branching rollers corresponding to the guide grooves. The branching rollers can be extended to and withdrawn from a position where they are guided through the guide grooves and a position where they are free. Whether the track guided vehicle runs straight or shifts to a branch line is controlled by selecting the branching roller guided by the corresponding guide groove. Further, in the entire running track except for its branching portion, guide wheels are guided using a vertical portion of the running track. However, this track guided vehicle system requires the pair of guide grooves to be provided for the branching control. Consequently, the running track has a complicated shape.
It is an object of the present invention to provide a track guided vehicle system that can use a simple configuration to determine whether the track guided vehicle runs straight or shifts to a branch line.
An additional object of the invention is to allow the height position of branching rollers to be reliably controlled, thus ensuring that rectilinear progression and branching can be controlled.
An additional object of the invention is to prevent elevation and lowering of the branching rollers from interfering with guide rollers to eliminate the need to reduce speed in front of a branching portion and to allow a track guided vehicle to run stably through the branching portion at high speed either for rectilinear progression or for branching.